Allan Hancock Atlantic expedition / University of Southern California.

Report 4

Allan Hancock Atlantic expedition / University of Southern California.

Report 8

Tropical climate and vegetation simulations during the Heinrich event 1 using an Earth System Model of Intermediate Complexity (EMIC) - the University of Victoria Earth System-Climate Model (UVic ESCM)

Abrupt climate changes from 18 to 15 thousand years before present (kyr BP) associated with Heinrich Event 1 (HE1) had a strong impact on vegetation patterns not only at high latitudes of the Northern Hemisphere, but also in the tropical regions around the Atlantic Ocean. To gain a better understanding of the linkage between high and low latitudes, we used the University of Victoria (UVic) Earth System-Climate Model (ESCM) with dynamical vegetation and land surface components to simulate four scenarios of climate-vegetation interaction: the pre-industrial era, the Last Glacial Maximum (LGM), and a Heinrich-like event with two different climate backgrounds (interglacial and glacial). We calculated mega-biomes from the plant-functional types (PFTs) generated by the model to allow for a direct comparison between model results and palynological vegetation reconstructions. Our calculated mega-biomes for the pre-industrial period and the LGM corresponded well with biome reconstructions of the modern and LGM time slices, respectively, except that our pre-industrial simulation predicted the dominance of grassland in southern Europe and our LGM simulation resulted in more forest cover in tropical and sub-tropical South America. The HE1-like simulation with a glacial climate background produced sea-surface temperature patterns and enhanced inter-hemispheric thermal gradients in accordance with the "bipolar seesaw" hypothesis. We found that the cooling of the Northern Hemisphere caused a southward shift of those PFTs that are indicative of an increased desertification and a retreat of broadleaf forests in West Africa and northern South America. The mega-biomes from our HE1 simulation agreed well with paleovegetation data from tropical Africa and northern South America. Thus, according to our model-data comparison, the reconstructed vegetation changes for the tropical regions around the Atlantic Ocean were physically consistent with the remote effects of a Heinrich event under a glacial climate background.

Results of Heinrich event 1 simulation from the University of Victoria Earth System-Climate Model (UVic ESCM) and the Community Climate System Model (CCSM3)

We investigated changes in tropical climate and vegetation cover associated with abrupt climate change during Heinrich Event 1 (HE1, ca. 17.5 ka BP) using two different global climate models: the University of Victoria Earth System-Climate Model (UVic ESCM) and the Community Climate System Model version 3 (CCSM3). Tropical South American and African pollen records suggest that the cooling of the North Atlantic Ocean during HE1 influenced the tropics through a southward shift of the rain belt. In this study, we simulated the HE1 by applying a freshwater perturbation to the North Atlantic Ocean. The resulting slowdown of the Atlantic Meridional Overturning Circulation was followed by a temperature seesaw between the Northern and Southern Hemispheres, as well as a southward shift of the tropical rain belt. The shift and the response pattern of the tropical vegetation around the Atlantic Ocean were more pronounced in the CCSM3 than in the UVic ESCM simulation. For tropical South America, opposite changes in tree and grass cover were modeled around 10° S in the CCSM3 but not in the UVic ESCM. In tropical Africa, the grass cover increased and the tree cover decreased around 15° N in the UVic ESCM and around 10° N in the CCSM3. In the CCSM3 model, the tree and grass cover in tropical Southeast Asia responded to the abrupt climate change during the HE1, which could not be found in the UVic ESCM. The biome distributions derived from both models corroborate findings from pollen records in southwestern and equatorial western Africa as well as northeastern Brazil.

The PAX II picture processing system at the University of Illinois, programming manual;

"C00-1018-1174."

The University of Illinois attached machine operating system: design criteria and program logic,

"Supported in part by National Science Foundation under Grant No. NSF-GP-7634."

ACSES : the automated computer science education system at the University of Illinois /

Bibliography: p. 141-143.

Material relating to retirement and death benefit system University of Illinois.

Includes tables of benefits.

Recommendations relating to retirement and death benefit system of the University of Illinois.

Includes tipped in "Digest of legislative bill for University retirement system".

A report on the planning, operation and funding of California's highway system.

"March 1988."

University of Michigan executive system for the IBM 7090 computer.

Mode of access: Internet.

Nominations of Mary Schapiro, Christina D. Romer, Austan D. Goolsbee, Cecilia E. Rouse, and Daniel K. Tarullo : hearing before the Committee on Banking, Housing, and Urban Affairs, United States Senate, One Hundred Eleventh Congress, first session, on nominations of Mary Schapiro, of New York, chairman-designate, Securities and Exchange Commission; Christina D. Romer, of California, chairman-designate, Council of Economic Advisors; Austan D. Goolsbee, of Illinois, member-designate, Council of Economic Advisors; Cecilia E. Rouse, of New Jersey, member-designate, Council of Economic Advisors; Daniel K. Tarullo, of Maryland, member-designate, Board of Governors of the Federal Reserve System, January 15, 2009.

Shipping list no.: 2009-0407-P.

A system of anatomy : from Monro, Winslow, Innes, and the latest authors. Arranged, as nearly as the nature of the work would admit, in the order of the lectures delivered by the professor of anatomy in the University of Edinburgh : in two volumes ...

Contiene : Vol. I - Vol. II.

Proceedings of the International Symposium on Magnet Technology, Stanford Linear Accelerator Center, Stanford University, Stanford California, September 8-10, 1965.

Mode of access: Internet.

Typography, books, and printing by Grant Dahlstrom: exhibition beginning May 15, 1946 through June 15, 1946, Treasure Room, Edward L. Doheny, Jr. Memorial Library, University of Southern California.

Check list.